2 2 BIBLIOGRAPHY. 



Contemporaneously with the earh'er publications of Stein as above 

 recorded, mention must be made of the work of Maximilian Perty, ' Zur 

 Kentniss kleinstcr Lebensformen,' published at Bern in the year 1852. 

 This treatise, like the earlier ones of Muller and Ehrenberg, embraces 

 an account, with illustrations, of a heterogeneous assemblage of micro- 

 scopic aquatic beings, including Rotifera, Rhizopods, and Bacillaria in 

 addition to the ordinary Infusoria. These latter are, however, together 

 with the Rhizopoda, separated by Perty from the associated animal and 

 vegetable organisms, and -collated together as distinct classes of a sub- 

 kingdom, essentially identical with the Protozoa of Von Siebold, but 

 upon which he conferred the new title of the Archezoa. The class of 

 the Infusoria is further divided by Perty into the two orders of the 

 Ciliata and Phytozoida, the former comprising all the ordinary ciliate 

 animalcules, and the latter flagellate organisms generally, whether of an 

 animal or vegetable nature. The innumerable infusorial forms figured and 

 described by Perty were collected by himself entirely in the vicinity of the 

 Bernese Alps, and embrace many new species, some of which have not been 

 since met with, while a few, such as his Eiitreptia viridis and Malloinonas 

 Plosslii, are delineated in this present volume after examination, for the first 

 time, with the higher magnifying powers of the compound microscope in 

 its present comparatively perfected state. Taken as a whole, Perty's illus- 

 trations of the Infusoria, and of his Ciliata in particular, are exceedingly 

 rough and unsatisfactory, being inferior in many respects to those previously 

 given by Ehrenberg, and not to be compared with the contemporaneous 

 ones of Stein. The view taken by this author with reference to the organiza- 

 tion and internal structure of the Infusoria, is distinguished by its opposition 

 to both the unicellular one of Siebold and the pol3^gastric one of Ehrenberg. 

 In place of these, Perty substituted the interpretation that these microscopic 

 beings are composed of an aggregation of separate cells, none of which 

 have attained their complete development, but remain indistinguishably 

 united with each other. He thus, as presently related, anticipated to some 

 extent the views adopted by Max Schultze in the same direction. The 

 presence of any nervous, muscular, or other complex organization he 

 entirely denied, as also that of a distinct internal parenchyma, the body 

 being described by him as composed wholly of simple contractile substance. 

 The thickly ciliated cuticular surface of Stentor and other forms he never- 

 theless compared to the ciliated epithelium of more highly differentiated 

 organic types. 



The first onslaught upon the Acineta theory enunciated about this 

 date by Stein, was delivered by Johannes Lachmann, who, in Muller's 

 'Archives ' for the year 1856, adduced testimony strongly in favour of the 

 independent organization oi Acineta and its allies, showing the character- 

 istic manner in which they preyed upon other Infusoria, and their mode of 

 reproduction through the separating of a portion of the central nucleus or 

 endoplast. Corroborative evidence of a still more conclusive character, and 



